A sharpening device generally modifies a cutting edge of a cutting device to an appropriate shape. The sharpening device generally operates by grinding or abrading away material on the cutting edge with an abrasive substance harder than the material of the cutting edge. A polishing process may also be applied to the cutting edge to increase smoothness and correct for possible deformations.
A manual sharpener generally comprises a sharpening stone comprising a sharpening surface with abrasive grains and a surface without abrasive grains, the surface without abrasive grains comprises a groove. The groove generally extends along a direction substantially perpendicular to a sharpening direction. With the manual sharpener, a sharpening residue generated by sharpening with the sharpening stone may remain on the sharpening surface, and may reduce an effectiveness of the sharpening surface.
An electric knife sharpener generally comprises a rotational sharpening member coupled to an output shaft of an electric motor. The rotational sharpening member rotates and contacts the cutting edge of the cutting device, thereby sharpening the cutting edge of the cutting device. In the electric knife sharpener, the cutting edge to be sharpened may be repelled by the rotational sharpening member. If the cutting edge is repelled, an angle at which the cutting edge is sharpened may not be stable, thereby reducing a cutting quality of the cutting edge.
Therefore, there is a need for a sharpener that maintains a stable angle of the cutting edge during sharpening.